Ethernet Switching
Reply
Contributor
eagle107
Posts: 38
Registered: ‎09-15-2008
0

What are the hottest/latest LAN network designs?

 

Everyone,

 

This is a general question.  Does anyone know what are the latest/hottest LAN designs trends being used for large scale campus and data center networks these days?  Are you using L3 designs such as OSPF with ECMP or L2 designs in these large scale networks?  I am trying to figure out if using L3 design with OSPF and ECMP is becoming passé.  Thanks for the input in advance.        

Distinguished Expert
keithr
Posts: 979
Registered: ‎09-10-2009
0

Re: What are the hottest/latest LAN network designs?

In my opinion, you're asking the wrong question.

 

There is no single network design that's going to solve every need.  OSPF with ECMP isn't going anywhere.  L3 is quite alive and kicking, and there will always be a need for networks to operate at multiple layers for different purposes.  That's why they are layers.  :smileyhappy:

 

The "right" network design is always going to be a function of a few different variables:

- What problem are you trying to solve?

- What resources do you have available?  Equipment, budget, engineering talent, etc.?

- What problem are you trying to solve?

- What are the primary goals?  Simple design?  Cutting edge?    Stability?  Resilience?  Performance?

- What problem are you trying to solve?

- What is the environment in which the network will be designed to support?

And, most importantly:

- What problem are you trying to solve?

 

Notice a trend?  :smileyvery-happy:

 

"Flatter" networks are becoming trendy for data centers, especially with the push for converging the traditional ethernet/IP LAN with the storage fabrics (Fibre Channel SAN, etc.)  Most of the major vendors have a version of a flattened network.  Juniper has Qfabric.  Brocade has VCS.  Cisco has Unified Fabric (I think that's what they're calling it).  All aim to do the same basic thing -- virtualize the data center network into a single, large, flattened L2 fabric where every endpoint thinks it's one hop (logically) from any other endpoint.  From what I've seen, all the vendors have their hits and misses with actually turning "on paper" into reality.

 

If I were designing a brand new data center from the ground up with the freedom to choose how I wanted to build the networking, would I explore such a design?  Sure, I would explore it.  But, if I didn't feel that it met my needs and brought significant advantages to the table to outweigh the new challenges it would bring, I might stick with a more traditional design.  It would all depend, again, on the exact goals I was trying to solve.  Some data centers might be 5 9's, while others might be entirely focused on minimal latency or ridiculous throughputs (but maybe latency doesn't matter)...etc.

 

L2 networks are not going to replace L3 designs for enterprise deployments, campuses, WAN links (obviously), etc.  OSPF, BGP, MPLS... these are our friends, and will be around for a very long time.

 

I would say don't get caught up in trends or whatever the hot item of the week is.  CTO's like to read weekly publications and then ask "hey, why aren't we doing this cool stuff?" and the engineers have to respond with things like "We don't have millions of dollars" or "it's extremely immature technology right now."  Evaluate the goals and scope of the project, factor in budgets and engineering talent (maybe you don't have an engineering staff that's really comfortable with a new network design paradigm right now?), and determine the best, simplest (always keep it simple), long-term path for each need you're trying to address.

 

 

-kr


---
If this solves your problem, please mark this post as "Accepted Solution."
Kudos are always appreciated.
Contributor
eagle107
Posts: 38
Registered: ‎09-15-2008
0

Re: What are the hottest/latest LAN network designs?

Thanks.  We are reviewing our network standards which are to use L3 designs in our large core networks.  We have heard from some network vendors that distributing L3 everywhere is an old model.  Using newer protocols that other vendors have in their network equipment can aggregate the LAN cores with a L2 (flatten) design and eliminate the need for OSPF/ECMP distribution, which many vendors (as you stated) believe will solve virtualization issues.  What worries us is the LAN cores are now susceptible to loops if these “new protocols” still rely on STP domains.  We just want to make sure our network standards are not out-of-date and that we are not missing a new trend out in the industry. 

Distinguished Expert
keithr
Posts: 979
Registered: ‎09-10-2009
0

Re: What are the hottest/latest LAN network designs?

For what it's worth, the newer L2 designs do away with STP by using routing bridges (rbridges, aka TRILL).  It's basically IS-IS that runs at layer 2.  So, you can have true multipath and redundant L2 networks without worrying about loops.

 

Again, though, whether that is appropriate for your LAN is going to depend entirely on your needs and your environment.  Don't let a vendor feed you the "this solves everything" nonsense.

-kr


---
If this solves your problem, please mark this post as "Accepted Solution."
Kudos are always appreciated.
Copyright© 1999-2013 Juniper Networks, Inc. All rights reserved.